1. Field of the Invention
This invention relates to the counting of goods manufactured by a die casting machine. More particularly, the invention relates to an arrangement (apparatus and method) for automatically counting die casting manufactured goods. The invention automatically distinguishes goods produced during a "waste shot" from those produced during normal operation of the die casting machine.
2. Description of the Related Art
Die casting machines are widely used for producing goods made of aluminum and other metals. Die casting machines are generally operated, in one of three modes: a "test shot" mode, a "waste shot" mode and a "normal" mode during which goods are produced. A "test shot" is an operating procedure carried out to determine the various conditions under which the die casting machine will be later operated during "normal" mode operation for continuously producing goods which satisfy production specifications.
The various conditions and parameters defining normal mode are determined by carrying out one or more test shots. For example, one condition that may need to be determined during one or more test shots might be the critical speed of a plunger during part of the injection molding process. For example, in the case of a two stage injection system, one or more test shots might be used to determine the critical speed of the plunger during a low speed injection process for filling a mold with molten metal. This is the speed required to avoid causing porosity in the die casting manufactured goods. Of course, this is only one example.
Other conditions may also be determined during test shots, such as, for example:
a) the speed of the plunger of injection during a low speed injection process;
b) the timing of a change of plunger speed from low speed to high speed; and
c) the timing for increasing the pressure of molten metal (intensification) and the pressure thereof, and the like. Of course other conditions may also be determined during a test shot.
After operating in test mode for one or more test shots to determine various operating conditions, the die casting machine is operated in waste shot mode. One or more waste shots are carried out. Typically, waste shots are carried out at various times:
during warming up of the die casting apparatus at initial start-up; PA1 during warming up of the apparatus after a pause in its operation; and PA1 when molten metal is loaded into a metal mold cavity to stabilize the temperature of the metal mold.
After carrying out one or more waste shots, the die casting apparatus is operated continuously for some time in its normal mode to manufacture die cast goods. During normal mode operation, the various operating parameters determined during test mode operation are used. Assuming that the various operating parameters were correctly determined during test shots, the goods produced should meet design specifications. The machine is operated in normal mode until the desired number of manufactured goods are produced. Thus, it is desirable to be able to count the individual goods produced.
It is known to provide a counter and a selecting switch for counting die cast manufactured goods. After a waste shot the selecting switch is manually turned on to actuate the counter. However, according to known practice, it is difficult to automatically count only the goods from normal shots because of the test shot and waste shot operations. The operator of a die casting machine must distinguish whether each piece of goods produced is from a normal shot, a test shot or a waste shot. The operator manually turns on and off the selecting switch to actuate the counter.
Accordingly, it is desirable to provide an arrangement for automatically counting manufacturing goods in a die casting machine that would eliminate the need for this type of operator involvement.